Plastic threaded insert for forming voids in concrete products

ABSTRACT

A protective plug for a concrete coil insert or the like. The plug consists of a monolithic plastic unit including a tapered head and a threaded cylindrical portion extending therefrom in concentric relationship thereto. The head is hollow and has a wall extending diametrally thereacross. The unit is intended to be inserted into a coil insert which is retained within a casting of concrete. The protective plug is nailed or otherwise fastened to a wooden form in which the concrete is to be poured and the coil insert is threaded thereupon. After the concrete is cast, the concrete unit is removed from the form and the protective plug is unscrewed from the coil insert.

United States Patent 1 Ilukowicz 1 June 17, 1975 [75] Inventor: Robert John Ilukowicz, Coram,

[73] Assignee: Preco Industries, Ltd., Plainview,

22 Filed: Mar. 26, 1973 211 App]. No.: 345,183

[52] use]. ..249/59; 249/83; 249/177 51 Int. Cl ..B29d1/00 58 Field of Search ..249/42-43,

249/59, 63, 85, 91, 96-97, 175, 177, 183, 216-217, 187, 205, 207, 83; 52/699-700, 705; 85/1 F, 41, DIG. 2

1,970,860 8/1934 Lowell 249/140 2,366,401 l/1945 Haskell 249/59 2,959,835 11/1960 Gates 3,685,782 8/1972 KowelL.

3,685,783 8/1972 Hilson 3,688,454 9/1972 Wolfcarius 52/705 Primary Examiner-Robert D. Baldwin Assistant Examiner-John McQuade Attorney, Agent, or Firm-Roberts & Cohen [57] ABSTRACT A protective plug for a concrete coil insert or the like. The plug consists of a monolithic plastic unit including a tapered head and a threaded cylindrical portion extending therefrom in concentric relationship thereto. The head is hollow and has a wall extending diametrally thereacross. The unit is intended to be inserted into a coil insert which is retained within a casting of concrete. The protective plug is nailed or otherwise fastened to a wooden form in which the concrete is to be poured and the coil insert is threaded thereupon. After the concrete is cast, the concrete unit is removed from the form and the protective plug is unscrewed from the coil insert.

8 Claims, 10 Drawing Figures PATENTEIJJUN]? I975 3,889,916

FIG.

FIG. 2

PATENTEDJUN 1 7 I975 PLASTIC THREADED INSERT FOR FORMING VOIDS IN CONCRETE PRODUCTS FIELD OF INVENTION This invention relates to protective plugs for concrete coil inserts and more particularly to units adapted to be nailed or otherwise fastened to concrete forms for the subsequent threading thereupon of coil inserts which are to be embedded in the cast concrete. The in vention also relates to tools therefor.

BACKGROUND Removal concrete insert plugs are known such as, for example, in the I. G. Haskell US. Pat. No. 2,366,401 wherein is disclosed a removable concrete insert device having a tapered shank at one end portion and having at its opposite end an integral stub extension portion adapted for engagement into the body of pouring forms. The plug has intermediate its stub and shank an integral radially, outwardly extended shoulder member which has one of its faces smooth and tapered inwardly and upwardly toward the tapered end of the shank. The plug may be installed on a wooden form by means of a screw and washer or may be nailed thereto, both of these operations being effected from the outside of the mold. Moreover, the shank of the unit while being tapered is not threaded along the entire extent thereof and is not particularly well suited for cooperation with coil inserts of the type with which the invention is concerned.

Additional inserts are to be found in the C. I. Williams US Pat. No. 1,680,923 and in the J. M. Willard US. Pat. No. 1,808,912. However, these units are only with difficulty associated with the cooperating concrete forms and moreover, are not intended for cooperation with the coil inserts with which the units of the invention are adapted to be used.

Still further inserts and units can be found in the S. S. Colt US. Pat. Nos. 2,001,052 and 2,270,035. These units suffer the disadvantages noted hereinabove and are not intended for cooperation with the coil inserts with which the units of the invention are adapted to cooperate.

Still further types of inserts or units having somewhat remote relationship to the invention are to be found in US. Pat. Nos. 359,735; 505,778; 1,970,860; 2,480,899; 2,683,287; 2,857,646; 3,054,145; and 3,112,540.

None of the aforegoing units are especially well adapted for use with wooden or steel forms for the casting of concrete, in which concrete is to be embedded at least one coil insert which serves the purpose of providing for connection to the cast concrete slab which is formed thereby for permitting the same to be transported for use and installation, or which coil inserts permit the threaded attachment of various types of appliances.

SUMMARY OF INVENTION crete and the like. i

Yet another object of the invention 18 to provide a protective plug adapted to be mounted on a wooden or steel concrete form which serves for the subsequent mounting of a coil insert and which maintains a required insert depth below the associated concrete surface.

Still another object of the invention is to provide an improved protective plug for a concrete coil insert which is readily detached from the latter.

Yet another object of the invention is to provide a protective plug for a coil insert which can be used for plugging coil insert holes in concrete structures after erection of the latter.

A further object of the invention is to provide improved protective plug' for a concrete coil insert which is easy to install and which effectively holds and positions the coil insert in or on a form.

Still another object of the invention is to provide an improved lightweight protective plug for a coil insert.

To achieve the above and other of its objectives, there is provided in accordance with the invention a protective plug for a concrete coil insert or the like, said plug comprising a monolithic plastic unit including a tapered head in the shape of a truncated conical form and a threaded cylindrical portion extending therefrom in concentric relationship thereto. In accordance with a preferred embodiment of the invention, the aforesaid plastic is a high density copolymer consisting of a mixture of polyethylenes with a density of about 0.94 to 0.97.

According to a feature of the invention relating to the removal thereof from a coil insert, the aforesaid head is provided with a slot adapted to receive a screwdriver or the like and is further provided in said slot with a polygonal recess serving to receive the extremity of an Allen wrench.

In accordance with yet a further feature of the invention, holes are provided which extend through the aforesaid head on opposite sides of the slot whereby said head can be readily nailed 0r screwed to a wooden or steel concrete form or the like.

According to one embodiment of the invention, the head may be substantially hollow and will include walls encircling the aforesaid holes and slot.

Advantageously, the plastic insert protective unit of the invention is not effected by vibrations as much as would be a steel or other counterpart.

Still further and advantageously, the protective plug of the invention protects the associated coil insert during finishing operations and during storage such as against rain water, acid and other foreign matter.

It is conventional in the use of devices for. the same general purpose as the protective plug of the invention to utilize masking tape to prevent leakage. The protective plug of the invention, however, eliminates the use of masking tape to prevent such leakage.

Still further, the protective plug of the invention is advantageously economically produced and reuseable and is readily manufactured with mass production techniques.

Additionally, a special tool is readily fabricated for use with the above insert.

BRIEF DESCRIPTION OF DRAWING The invention will be more readily understood from the following detailed description taken in connection with the accompanying drawing in which:

FIG. 1 illustrates in side sectional view the installation of a protective plug, provided in accordance with the invention, on a wooden concrete form of which a fragmentary sectional view is shown;

FIG. 2 is a top view of the structure illustrated in FIG. 1 with a coil insert mounted or installed on the protective plug;

FIG. 3 is a view corresponding to FIG. 2 with the concrete poured into the concrete form, the form having been removed and the plug having been detached from the coil insert which is left embedded in the concrete;

FIG. 4 is a front view of a protective plug provided in accordance with one embodiment of the invention;

FIG. 5 is a front view of a protective plug provided in accordance with a second embodiment of the invention;

FIG. 6 is a sectional view taken along line VIVI in FIG. 5;

FIG. 7 is an enlarged fragmentary view of the threaded portion of the protective plug provided in accordance with either of the aforegoing embodiments of the invention;

FIG. 8 is an end view of a tool to be used with the plug of FIGS. 5 and 6. v

FIG. 9 is a side view of the tool of FIG. 8; and

FIG. 10 is a side view perpendicular to that of FIG. 9.

DETAILED DESCRIPTION For the casting of concrete or the like, wooden structures are frequently employed to establish forms in which the concrete can be cast and left to cure until it has adequately hardened.

With respect to the cast concrete objects which result, these are frequently pre-cast slabs or parts which have to be moved from the position in which they are manufactured to a position of utilization. For this purpose, it is desirable to provide threaded receptacles to which threaded connection can be made so that the slabs or other such parts can be moved by cranes or other such types of apparatus. In addition, it is frequently desirable in various types of cast concrete masses to provide threaded receptacles to which threaded connection can be made for purposes of the connecting thereto of various types of appliances or utility devices such as, for example, hooks, eyelets and so forth.

In FIG. 1 is illustrated a section 10 of a wooden form with which to take the initial steps preparatory to providing for the embedding of a threaded receptacle in a concrete mass. A protective plug 12 provided in accordance with the invention is nailed to the wooden form by means of nails 14 and 16. These nails, as will be shown, are driven through holes provided in the plug for that purpose and the plug itself is a monolithic structure made of plastic as will be described in greater detail hereinafter.

It is to be noted from FIG. 1 that the nailing operation takes place on the inside surface 18 of the mold or in other words against the surface which will be facing the semi-liquid concrete when the latter is poured. This nailing operation takes place on the inside surface 18 which means that the plastic plug 12 can be very accurately positioned where desired.

As illustrated in FIG. 2, which is a top view of the structure previously discussed with respect to FIG. 1, a coil insert 20 is illustrated. This coil insert 20 is not a part of the invention and no claim is herein made with respect to the inventorship thereof. However, an understanding of its construction will facilitate an understanding of the protective plug of the invention and how the plug functions in its environment.

More particularly, one type of coil insert consists of a U-shaped element 22 formed of a rod or wire of steel or the like, said rod being preferably circular in crosssection with a diameter of, for example, A; or A of an inch or the like.

Welded between the legs of the loop 22 is a helical receptacle 24 consisting of the same type of rod or wire as that from which the loop 22 is made. The helical receptacle 24 is held to the legs of the loop 22 with the turns of the receptacle in close proximity to one another thereby forming an internally threaded receptacle.

In FIG. 2, it will be noted that the ends 26 and 28 of the loop 22 abut against the head 30 of the protective plug 12. It should be noted from FIGS. 1 and 2 that integral with said head 30 is a threaded axial extension 32 having the form of a threaded cylindrical portion, the pitch of which corresponds to the internal thread of the helical receptacle 24. Thus thed'evice or coil insert 20 can be threaded 'on the protective plug 12 and, more particularly, on .the threaded cylindrical portion 32 thereof when the plug has been fixed in position on the wooden form 10 I i In FIG. 3, the concrete mass 34 has been poured into the form 10 which has been removed since the mass 34 has been cured and hardened. The coil insert has been left embedded in the concrete mass 34 and the protective plug 12 has been removed. The protective plug 12 which has been removed may now be reused for another similar operation or may subsequently be reinstalled in the coil 20 to protect-against the corrosive action of rain water or acid or the like.

The removal of the plug 12 leaves a tapered opening indicated at 36 wherethrough access may be had to the helical receptacle 24. Similarly, the threaded receptacle 24 is available to the exterior of the concrete mass 34 for purposes of the installation of an appliance such as has been mentioned hereinabove.

FIG. 4 is a front end view of a protective plug provided in accordance with one embodiment of the invention. In the front end face of the plug is provided a rectangular slot 40 having a width S1 which is preferably in the order of A of an inch. It has a length L1 which may generally be in the range of about an inch to an inch and a half or the like depending upon the overall diameter D of the front face which may preferably and usually run in the order of two inches plus or minus a quarter of an inch.

Straddling the slot 40' are two nail holes 42 and 44. These nail holes may have, for example, a diameter of 3/32 of an inch or the like and are intended to accommodate and guide the nails 14 and 16 as appears in FIG. 1. The holes 42 and 44 extend through the head of the unit and may be provided with any convenient diameter to accommodate nails which will affix the unit to a wooden form or the like.

In the bottom of the slot 40 is a polygonal recess 46. This polygonal recess which is in the illustrated case hexagonal is intended to accommodate the end of an Allen wrench or the like and both the slot 40 and the recess 46 are intended for the unscrewing of the protective plug from the coil insert 20 after installation and embedding of the latter in a concrete mass.

The embodiment illustrated in FIG. 5 is provided with recesses 48 and 50 leavin gfiiametral walls 52 and 54 to form slot 40 and semi-circular walls 56 and 58 to form nail holes 42 and 44. These walls are preferably around an eighth of an inch in thickness but are susceptible of modification according to design requirements.

FIG. 6 illustrates a cross-section taken along line VI-VI of FIG. 5. In FIG. 6 will be seen the recesses 48 and 50 and the internal configuration of the head will also be more apparent. Furthermore seen in FIG. 6 are the walls 52 and 54 and the hexagonal recess 46 also seen in FIGS. 4 and 5.

The elongated cylindrical portion 32 is, as has been noted above, a threaded portion. Its outer diameter D1 may, for example, be about A of an inch and its minimum diameter D2 may be, for example, about /a of an inch. These dimensions, it will be appreciated, can be readily modified in order to adapt to the threaded receptacle 24. The length L2 in FIG. 1 is preferably a minimum of about three inches and, in the illustrated embodiment, it is about 3 inches.

The depth L3 of the head is equal to the minimum acceptable embedding of the coil insert into the associated concrete mass. This will generally be A2 or of an inch. The illustrated embodiment is of an inch.

While the diameter of the front face of the head of the coil insert has been generally discussed above, the diameter of its inner face is indicated at D3 in FIG. 6. This dimension for the illustrated embodiment is about 1 /2 inches with a suitable range (say i A of an inch) being provided according to the angle of taper indicated at A with respect to the inclined surface of the head 30. This angle A generally and preferably lies within the range of about to 30 to provide for removal of the plug from the concrete.

The protective plug of the invention is a monolithic plastic unit. A high density copolymer is preferred as the plastic which will provide a lightweight plug which is resistant to a wide variety of corrosive fluids or the like. It will moreover be a plastic which is readily molded into a form which has a relatively smooth surface which will prevent the adhesion of concrete thereto thereby facilitating removal of the embedded coil. The protective plug of the invention is preferably a mixture of polyethylene having a density of 0.94 to 0.97. Preferably the plastic is uncolored although color coding can be introduced if necessary or desirable.

From what has been described above, it will now be evident that the invention provides a protective plug for a concrete coil insert or the like, said plug comprising a monolithic truncated conical head and a threaded cylindrical portion extending therefrom in concentric relationship thereto.

The head may be provided with a slot adapted to receive a screwdriver or the like to facilitate removal from an embedded coil insert and is further provided in said slot with a polygonal recess serving to accommodate an Allen wrench or the like. Holes are preferably provided extending through the head on opposite sides of the slot whereby the head can be nailed to a wooden concrete form or the like. The head may be substantially hollow and thereby be provided with walls encircling the aforesaid holes and slot. The head is preferably at least about /2 of an inch thick and has a taper towards said cylindrical portion of about 15-30. The cylindrical portion is at least about three inches in length.

The cylindrical portion has a thread which is adapted to that of the threaded receptacle 24 described hereinabove. This thread is preferably in the order of about 4 /2 turns per inch although a variation in this pitch is possible.

With reference to FIG. 7 it will be seen that the pitch is constituted by a series of circular grooves indicated by way of example at 60 and 62, these being delineated by ridges 64, 66 and 68. The grooves are preferably parts of a circle and, for example, a radius R of the circle for grooves 60 is indicated. This radius is preferably in a range of about l/16 to /8 of an inch depending upon the size of the rod or wire used in the manufacture of the coil insert 20.

Each groove, such as the groove 62, constitutes a part of a circle, the angle P for which is indicated in FIG. 7. This angle lies within a range, for example, of 40 to 70 and preferably within the range of 50 to 60. The radius R and the angle P mentioned hereinabove with respect to FIG. 7 can be adapted to the design of the coil insert with which the'plug of the invention is to be employed.

Although screwdrivers and Allen wrenches have been indicated as removal tools, FIGS. 8-10 illustrate an aluminum block tool especially useful for the plug of FIGS. 5 and 6.

This block is generally indicated at and is provided with a transverse bore 82 as well as a parallel and diametral slot 84 which straddles walls 52 and 54 (FIG. 5). The block 80 is moreover provided with parallel diametrally opposed semi-circular recesses 86 and 88 to accommodate walls 56 and 58. Bore 82 is above the level of said slot 84.

Prongs 90 and 92 which result fit into recesses 48 and 50 (FIG. 5) and a rod inserted through bore 82 will give sufficient mechanical leverage to permit the detaching of the associated plug from a coil insert.

There will now be obvious to those skilled in the art many modifications and variations of the construction set forth hereinabove. These modifications and variations will not depart from the scope of the invention if defined by the following claims.

What is claimed is:

1. A protective plug for a concrete coil insert or the like, said plug comprising a monolithic plastic unit including a tapered head in the shape of a truncated conical form and a threaded cylindrical portion extending therefrom in concentric relation thereto, said plastic being a high density polyethylene with a density of about 0.94 to 0.97, said head being provided with diametrally spaced holes extending at least substantially through said head whereby said head can be nailed to a wooden concrete form, said head being provided with a diametral slot extending between said holes which are located symmetrically on opposite sides of the slot.

2. A plug as claimed in claim 1 wherein said head is at least about one-half inch in thickness and has a taper towards said cylindrical portion of about 15-30.

3. A plug as claimed in claim 2 wherein said cylindrical portion is at least about three inches in length and is threaded along at least substantially the entire extent thereof.

4. A plug as claimed in claim 3 wherein said portion has a thread of about 4 /2 turns per inch.

5. A plug as claimed in claim 4 wherein said thread has a maximum diameter of about X; of an inch and a minimum diameter of about /8 of an inch.

6. A plug as claimed in clztim 3 wherein said cylindriabout 40 70 of a circle. cal portion has a thread formed of a particular recess 8. A plug as claimed in claim 7 wherein the recess is having a radius of about 1/16 to /3 of an inch. about 50 60 of a circle.

7. A plug as claimed in claim 6 wherein the recess is 5 

1. A PROTECTIVE PLUG FOR A CONCRETE COIL INSERT OR THE LIKE, SAID PLUG COMPRISING A MONOLITHIC PLASTIC UNIT INCLUDING A TAPERED HEAD IN THE SHAPE OF A TRUNCATED CONICAL FORM AND A THREADED CYLINDRICAL PORTION EXTENDING THEREFROM IN CONCENTRIC RELATION THERETO, SAID PLASTIC BEING A HIGH DENSITY POLYETHYLENE WITH A DENSITY OF-ABOUT 0.94 TO 0.97, SAID HEAD BEING
 2. A plug as claimed in claim 1 wherein said head is at least about one-half inch in thickness and has a taper towards said cylindrical portion of about 15*-30*.
 3. A plug as claimed in claim 2 wherein said cylindrical portion is at least about three inches in length and is threaded along at least substantially the entire extent thereof.
 4. A plug as claimed in claim 3 wherein said portion has a thread of about 4 1/2 turns per inch.
 5. A plug as claimed in claim 4 wherein said thread has a maximum diameter of about 3/4 of an inch and a minimum diameter of about 5/8 of an inch.
 6. A plug as claimed in claim 3 wherein said cylindrical portion has a thread formed of a particular recess having a radius of about 1/16 to 1/8 of an inch.
 7. A plug as claimed in claim 6 wherein the recess is about 40* - 70* of a circle.
 8. A plug as claimed in claim 7 wherein the recess is about 50* - 60* of a circle. 